Global advances in integrated hydrologic and water quality modeling for environmental assessment

The Hydrologic and Water Quality System (HAWQS) is a web-based modeling platform that integrates hydrological and water-quality processes to simulate runoff, infiltration, evapotranspiration, nutrient transport and sediment dynamics across multiple spatial scales. Developed at Texas A&M University and adopted by the U.S. EPA, HAWQS supports watershed assessment, policy development and climate adaptation planning. This review summarizes over a decade of HAWQS applications. It examines related platforms, including HAMSA, SUPer and HUMID, which extend HAWQS concepts using regional datasets and alternative modeling frameworks such as SWAT+. Case studies demonstrate significant environmental benefits from HAWQS-guided management practices, including substantial reductions in sediment and nutrient losses through riparian buffers, conservation measures and reforestation efforts. Economic assessments indicate that these improvements can generate considerable annual benefits for affected watersheds. Although HAWQS is highly versatile, its performance depends on quality input data and effective calibration. Future integration with remote sensing and cloud computing could improve real-time decision support.